Bruce is also a regular columnist on MRH and frequents this forum often. Anyhow, here is the link to his website.

http://mrdccu.com/

It's the draw from the locomotives sitting or running on the track that will really affect how many amps you need.

I'm thinking that I'd want at least one more power booster for that layout, just in order to break it down into power districts, with a booster on each level, and "circuit breakers" like the DCC Specialties PSX  or the NCE EB-1 to separate blocks of track into power districts so that one short doesn't take everything down - and makes it easier to isolate. 

Jeff, It will look like I have 20 locomotives on the layout, however, 5 or 6 of those will be non DCC, just stitting on non powered turntable spurs.

so about 14-15 N scale steamers.

Where can I find out about boosters and "power districts"?

On my old layout, I just had the main box and the extension plate.

I am not a DCC expert but I do have a MRC Prodigy Wireless system and I only use the 4A power supply with out any circuit protection.  In staging I probably have about 25 engines on powered tracks while I can run 2 trains or so each with 3 locomotives.  I do not have any problems at all with this.  Experts and literature probably would recommend at least another booster or circuit breakers but again it works for me fine for a number of years.

I only have two locomotives with sound but I think these latest sound decoders draw much more power than non-sound decoders.

I run my tortoise switch machines off a separate power supply which I would recommend.

I would just try using the 4A power supply.  If you have any problems get a booster but at least from my experience you may not need it.

My question was, could I run the 43 switch machines and 43 LEDs off the track power as suggested in the one set of instructions I have.

I know the Hoffmanns draw 0.05 Ampere, but do not know what LEDs draw, or even which LEDs I should get.

I did not want to run a second power line all around the layout as it is a double deck layout.

You're not the first person to ask about power districts here. When I put it in the Google Search box above on the right, this seemed a good thread to start with: http://model-railroad-hobbyist.com/node/4406

Thank You sir.

...approximately 2.5 to 3 amps with the 43 switch motors at 0.05A and 43 LEDs. Assuming 0.01A to 0.02A for the LEDs. that only leaves 1 to 1.5A for train power. I would do as Jeff suggests and use your  master unit to power one level and a booster for the other level.

You could also run a separate bus with its own booster just for the switch machines and LEDs. This is a good idea as I have seen instances where derailments on turnouts occur when the booster overloads and shuts down just as a control signal is sent to a switch machine and is lost.